Single protein from human leukocytes possesses 5-lipoxygenase and leukotriene A4 synthase activities.
Single protein from human leukocytes possesses 5-lipoxygenase and leukotriene A4 synthase activities.
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来自人类白细胞的单一蛋白质具有 5-脂氧合酶和白三烯 A4 合酶活性。
DOI：
10.1073/pnas.83.4.857
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发表时间：
1986
影响因子：
11.1
通讯作者：
B. Samuelsson
中科院分区：
文献类型：
--
作者：
C. Rouzer;T. Matsumoto;B. Samuelsson
白三烯A4 （LTA4）合成酶在粗人白细胞匀浆中的活性被发现对Ca2+和ATP的需求与先前注意到的5-脂氧合酶活性相似。采用硫酸铵分馏法、ac44凝胶过滤层析法和阴离子交换柱和羟基磷灰石柱的高效液相色谱法对5-脂氧合酶进行纯化，结果表明，LTA4合成酶活性与5-脂氧合酶共纯化，回收率相似，比活性增加。此外，这两种酶的活性在三种不同的高效液相色谱系统上完全溶出。纯化的LTA4合成酶的最大活性需要添加三个不可透析的刺激因子，其中两个是细胞质的，一个是膜结合的。这些发现与5-脂氧合酶活性相同。当与花生四烯酸孵育时，纯化的5-脂氧合酶将大约等于其内源性生成的5-羟基过氧二糖四烯酸（5-HPETE）的15%转化为LTA4。当酶利用花生四烯酸产生的5-HPETE时，LTA4的生产效率比外源提供5-HPETE时更高。这些发现表明，来自人类白细胞的单一蛋白具有5-脂氧合酶和LTA4合成酶活性，并且5-HPETE合成LTA4受调节5-脂氧合酶反应的相同复杂多组分系统的控制。
The activity of leukotriene A4 (LTA4) synthase in crude human leukocyte homogenates was found to have a similar requirement for Ca2+ and ATP as had been noted previously for 5-lipoxygenase activity. Purification of the 5-lipoxygenase using ammonium sulfate fractionation, AcA 44 gel-filtration chromatography, and HPLC on anion-exchange and hydroxyapatite columns demonstrated that LTA4 synthase activity copurified with the 5-lipoxygenase with similar recoveries and increases in specific activity. Furthermore, the two enzymatic activities coeluted exactly on three different HPLC systems. Maximal activity of purified LTA4 synthase required the addition of three nondialyzable stimulatory factors, two of which were cytosolic and one of which was membrane-bound. These findings were identical for 5-lipoxygenase activity. When incubated with arachidonic acid, the purified 5-lipoxygenase converted approximately equal to 15% of its endogenously generated 5-hydroperoxyicosatetraenoic acid (5-HPETE) to LTA4. LTA4 production was more efficient when the enzyme utilized 5-HPETE generated from arachidonic acid than when 5-HPETE was exogenously supplied as substrate. These findings suggest that a single protein from human leukocytes possesses 5-lipoxygenase and LTA4 synthase activities and that the synthesis of LTA4 from 5-HPETE is controlled by the same complex multicomponent system that regulates the 5-lipoxygenase reaction.